[PATCH 09/11] treewide: Convert custom kernel_param_ops .get callbacks to seq_buf via cocci

[Sean Christopherson]

On Thu, May 21, 2026, Kees Cook wrote:
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 07f4c7209ac0..00317774a90b 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -368,12 +368,16 @@ static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp)
>  	return ret;
>  }
>  
> -static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
> +static int vmentry_l1d_flush_get(struct seq_buf *s,
> +				 const struct kernel_param *kp)
>  {
> -	if (WARN_ON_ONCE(l1tf_vmx_mitigation >= ARRAY_SIZE(vmentry_l1d_param)))
> -		return sysfs_emit(s, "???\n");
> +	if (WARN_ON_ONCE(l1tf_vmx_mitigation >= ARRAY_SIZE(vmentry_l1d_param))) {
> +		seq_buf_printf(s, "???\n");
> +		return 0;
> +	}
>  
> -	return sysfs_emit(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
> +	seq_buf_printf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
> +	return 0;

For this one, can you manually change it to this?

	if (WARN_ON_ONCE(l1tf_vmx_mitigation >= ARRAY_SIZE(vmentry_l1d_param)))
		seq_buf_printf(s, "???\n");
	else
		seq_buf_printf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
	return 0;

>  }
>  
>  /*
> @@ -459,9 +463,11 @@ static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp)
>  	pr_warn_once("Kernel compiled without mitigations, ignoring vmentry_l1d_flush\n");
>  	return 0;
>  }
> -static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
> +static int vmentry_l1d_flush_get(struct seq_buf *s,
> +				 const struct kernel_param *kp)
>  {
> -	return sysfs_emit(s, "never\n");
> +	seq_buf_printf(s, "never\n");
> +	return 0;
>  }
>  #endif